On 04/24/2018 03:50 PM, Mirela Simonovic wrote:
Hi Julien,
Hi,
Sorry I forgot to answer to some part of the e-mail.
On Mon, Apr 23, 2018 at 1:28 PM, Julien Grall <julien.gr...@arm.com> wrote:
Hi Mirela,
On 20/04/18 13:25, Mirela Simonovic wrote:
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index d43c3aa896..9bb62c13cd 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1451,13 +1451,21 @@ err:
return page;
}
-static void __init setup_virt_paging_one(void *data)
+static void setup_virt_paging_one(void *data)
{
unsigned long val = (unsigned long)data;
WRITE_SYSREG32(val, VTCR_EL2);
isb();
}
+/* VTCR value to be configured by all CPUs. Set only once by the boot
CPU */
+static unsigned long __read_mostly vtcr_value;
VTCR is a register, so the type should be represented in term of bits (i.e
uint*_t).
I followed the type used in setup_virt_paging() and it's unsigned
long. However, the spec says the VTCR_EL2 is 32-bit register, meaning
that in the current implementation the type is not correct.
If I want the type to be correct in this patch Xen will not compile.
Are you suggesting to fix the type in existing implementation?
The unsigned long is just a workaround to avoid an extra variable for
the cast. As you introduce a static variable, then the cast become
unnecessary.
+
+void setup_virt_paging_secondary(void)
+{
+ setup_virt_paging_one((void *)vtcr_value);
That's fairly ugly. Is there any way to rework the interface? For instance,
because you have a static variable which contain the VTCR, you could just
use the variable in setup_virt_paging one.
I
If the argument provided to setup_virt_paging_one() is NULL within the
setup_virt_paging_one() I configure saved static vtcr_value? If that
is what you meant it was submitted in previous version of this patch
:)
Are you suggesting to revert the change to v1?
I would suggest a mix between v1 and v2. Something like:
static uint64_t vtcr;
static setup_init_paging_one(void *data)
{
WRITE_SYSREG(vtcr, VTRC_EL2);
[...]
}
r
void __init setup_virt_paging(...)
{
vtcr = val;
}
Potentially, you could drop val and use vtcr everywhere in
setup_virt_paging().
Cheers,
--
Julien Grall
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